Sam Allardyce says Sunderland's lack of consistency means he may be forced to make additions to the squad in January.
After successive victories against Crystal Palace and Stoke City last month, the struggling Premier League side have suffered three consecutive losses, the third of which came against Chelsea at Stamford Bridge on Saturday.
The 61-year-old manager is uncertain how to approach the next fixtures, starting with Manchester City away next Saturday, followed by the visit of Liverpool to the Stadium of Light, and believes signings could well be required when the transfer window opens next month.
"We've had a while to look at it and I'm disappointed with the lack of consistency," Allardyce said.
"We've seen some good things, back-to-back wins, which gave us an opportunity to go forward but we've dropped back into the mire again through our lack of results.
"A lot of players in that dressing room really know they've underperformed and they've got to do better.
"I've got to find a solution. If I can't find a solution in the squad I've got to find one in January and see where we go from there.
"It's a big worry in terms of where do I go next – what team do I pick, what system do I pick. Looks like I'm going to have to find a new system and players in that."
However, Allardyce was pleased to see his side put Chelsea under pressure during the second half, although they fell short of completing a comeback after Fabio Borini's strike.
"The only good thing I can say is that we never laid down and died after that.
"We could have easily gone under but we didn't, we came back and we started to create. We got the goal and then we saw Chelsea a little nervous."
